PURPOSE: To obtain the ventilation device capable of effectively preventing the instruction of rain water into the house and as well as of easily manufacturing.

CONSTITUTION: The ventilation device is formed rectangular so as to be able to insert its rear part through a rectangular ventilating hole 2 piercingly provided at the gable wall 1 of the house protrudedly into the house. Fitting flanges 5W8 for fitting a ventilating tube body 3 to the opening edges of the ventilating hole 2 of said gable wall 1 are fixedly provided at the opening edges of the front end opening 4 of the ventilating tube body 3 with its rear end closed. An opening 10 is formed at the upper peripheral wall 9 of the ventilating tube body 3 protruded into the house. Furthermore, drip pieces 11 and 12 to retrieve and drip water drops are provided suspendedly and parallel to the wall surface of said gable wall 1 at the inside of said upper peripheral wall 9. Due to the construction mentioned above, the intrusion of rain water into the house through the ventilating hole 2 can be effectively prevented and, because, for example, the major part of the device can be formed through the bending work of only two sheets of metal plates with minimum joining parts by welding 17 or the like, the device can be manufactured easily.